It is known to provide a spiral groove in the carbon brush contact surfaces of collector rings, particularly in collector rings of large industrial electrical generators or motors, and similar machinery. The grooves can serve various purposes. For example, the grooves help to reduce selective action of the brushes, which can cause catastrophic failure of the brush to ring contacts. After wear due to prolonged use, or after turning down, or re-truing of the collector ring contact surfaces, the grooves can be worn away, or become to shallow for optimal operation. For example, if the collector ring goes out of round, and needs to be re-trued, the re-truing operation can wear away the groove. Therefore, in such situations, the groove must be re-form-ed or enhanced in the contact surfaces of the collector rings. However, many of the known processes for initially creating such grooves, or for re-forming or enhancing such grooves are difficult to perform or are very time consuming. Therefore, it would be desirable to provide a new method and apparatus for creating or recreating grooves in the surfaces of collector rings.